Sewing machine handwheel



Sept. 30, 1969 l w. WATSON 3,469,471

SEWING MACHINE AnnwEL l Filed sept.. 13, 1967 u INVENTOR Wllllam Watson Y BY m52@ 7%!.4 @w

ATTO EY United States Patent 3,469,471 SEWING MACHINE HANDWHEEL William Watson, Duntocher, Scotland, assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Sept. 13, 1967, Ser. No. 667,552 Int. Cl. Gg 1/12` U.S. Cl. 74-552 4 Claims ABSTRACT oF THE DISCLOSURE A handwheel Vfor a sewing machine is described asbeing so formed that, when embodied in a sewing machine, the cost of manufacturing such machine is lessened. The handwheel in question has the necessary moment of inertia and the heavy duty requirements of a painted casting, but is substantially aesthetically damage-proof. The handwheel of the invention integrates a plastic exterior with a pulley casting, doing so in a way that not only causes the plastic to adhere directly to the pulley, but in a way that precludes cracking of the plastic as it grips the pulley.

BACKGROUND OF THE INVENTION Field of the invention The invention provides a handwheel for a sewing machine, which handwheel is adapted to be secured to the drive shaft of such machine, whereby the shaft in addition to being belt driven may be manually turned over for needle positioning purposes or the like, and which handwheel is so formed that it is not only virtually damage-proof, but aesthetically superior to existing handwheels.

Description of the prior art Prior art sewing machine handwheels, which are adapted to be replaced by handwheels according to the invention, are of cast iron, and are suitably painted with a hard enamel. To assure against chipping such enamel during sewing machine manufacture, the assembly line therefor is so set up that each machine has a dummy handwheel placed on it during machine manufacture, and when each machine is completed, its dummy handwheel is replaced by a first-quality (painted) handwheel. Such a procedure assures that the ultimate consumer will acquire an unmarred machine, but obviously leaves much to be desired from a manufacturing standpoint since it necessitates costly assembly-and-disassembly, and which costs are unfortunately passed on to the consumer.

SUMMARY OF THE INVENTION A handwheel according to the invention is so made that it may be placed on a sewing machine drive shaft during manufacture of such sewing machine, with no attendant need for such handwheel to be removed eventually because of aesthetic imperfections therein. Generally, the handwheel of the invention is of a pulley casting having an annular flange that supports a hub. The hub support is provided with openings extending from one face of the pulley to its other face. Suitably pre-colored plastic, as may be effected by a molding process, covers the annular flange, and passes through the hub support openings to sandwich the pulley casting therebetween. Since the pre-colored plastic is essentially integral with the handwheel, its tendency to chip is negligible; and since the plastic is homogeneously colored, Whatever imperfections may occur during molding, are substantially unapparent against their own background color.

A principal object of the invention is to provide improved handwheel apparatus for sewing machines.

3,469,471 Patented Sept. 30, 1969 ice Another object of the invention is to provide a sewing machine handwheel having a pulley casting that is sandwiched between a chip-proof pre-colored plastic that serves as the handwheel grip.

The invention will be described with reference to the FIG. 1 is a cutaway view of part of a sewing machine showing the details of construction of a handwheel according to the invention, and

FIG. 2 is a view of the handwheel of FIG. l taken .j generally along line 2-2 thereof.

Referring to the drawings, the bracket arm 10 of a sewing machine supports a drive shaft 12 in bearings 14. The sewing machine bracket arm 10 is provided with an opening 16 through which the handwheel 18 of the invention is adapted to extend. The shaft 12, which projects beyond its bearing support 14, has a bushing 20 with an annular flange 22 secured thereto by means of a set screw 24; and the bushing 20 is provided with inside threads 26. The handwheel 18 has a pulley portion 28 for accommodating a drive belt 30, and is essentially a casting provided with a hub 32 and an annular ange 34. The hub 32 is sufficiently axially longer than its support 45 to form an extended part 47 thereof. The handwheel 18 is placed on the bushing 20, and to assure that the handwheel 18 turns with the shaft 12, and vice versa, a clampscrew 36 is threaded into the bushing 20 to press, via a washer 38, the hub 32 against the bushing ange 22. To release the screw 36 so that the handwheel 18 may turn without turning the drive shaft 12, but in a way that assures that the handwheel remains on the shaft 12, say for bobbin winding purposes, a lock screw 37 is provided for engaging a tang 39 on the washer 38, such feature being amply disclosed in U.S. Patent No. 2,858,785.

As indicated, the portion of the handwheel 18 that extends from the bracket arm 10 is mostly of plastic 40 and, as such, is generally chip-proof. The plastic 40 provides an annular concavity 42, passes through apertures 44 in the hub support 45, and forms a ring 46 concentric with the hub 32. An annular peripheral notch 48 is provided in the flange portion 34 of the pulley to assure good bonding of the plastic to the handwheel casting.

In forming the handwheel of the invention, the pulley casting 28 is placed in an injection mold into which precolored plastic is inserted. The mold is so adapted that an annular undercut 50 is provided in the plastic, this being necessary to prevent cracking of the plastic as it hardens against the extended portion 47 of the hub 32. By virtue of the apertures 44, the injected plastic passes therethrough to grip tightly the pulley casting from both its sides, thereby to integrate the casting and its coating into a functional, but aesthetic, unit.

Handwheels by their nature are provided with high moments of inertia: This fact, along with the requirement for a durable pulley structure, has long been the basis for the requirement for heavy duty handwheel castings. Solid plastic handwheels, while difficult to damage (and therefore having well-preserved aesthetic qualities), are remiss when it cornes to such requirements. To paint a handwheel casting combines function with aesthetics but, as above noted, leaves much to be desired from a manufacturing standpoint. The present invention combines the aesthetics of plastic with the required functionality of a casting to effect an improved handwheel, thus representing one way to lessen sewing machine manufacturing costs.

While the invention has been described in its preferred form it is to be understood that the words which have been used are words of description rather than of limitation and that changes Vwithin the purview of the appended claims may be made without departing from the true scope and spirit of the invention.

Having thus set forth the nature of this invention, what is claimed herein, is:

1. A sewing machine handwheel having a pulley portion (28) with an annular flange (34), a hub portion (32), a support (45) interconnecting said hub portion (32) and said flange (34), said support being provided with at least one aperture (44) therethrough, and plastic (40) molded to said ange (34) and to both sides of said support (45) through said support aperture (44).

2. The handwheel of claim 1 wherein said pulley portion has a greater moment of inertia than the plastic molded thereto, and wherein said plastic is pre-colored.

3. The handwheel of claim 1 wherein said hub portion (32) is axially longer than said support (45) to form an 4 extended hub part (47), said plastic (40) being molded to said extended hub part (47) integrally with the plastic (40) molded to said flange (34) and to said support (45 and Said plastic (40) being provided with an annular undercut (50) proximate said extended hub part (47). 4. The handwheel of claim 3 wherein said flange (34) has an annular peripheral notch (48), which'notch iS adapted to be embedded by said plastic (40).

References Cited UNITED STATESV PMENTS"l 2,152,370 3/1939 woouard 74-552 3,225,624 12/1965 omer 112-220 XR FRED C. MATTERN, JR., Primary Examiner F. D. SHOEMAKER, Assistant Examiner 

